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A140886 Triangle read by rows: coefficients of the characteristic polynomials of Redheffer matrices. 0
1, 1, -1, 0, -2, 1, -1, -1, 3, -1, -1, 1, 3, -4, 1, -2, 5, -1, -6, 5, -1, -1, 5, -6, -3, 10, -6, 1, -2, 11, -21, 13, 8, -15, 7, -1, -2, 13, -33, 38, -11, -19, 21, -8, 1, -2, 16, -52, 86, -69, 7, 34, -28, 9, -1, -1, 12, -54, 124, -155, 90, 13, -56, 36, -10, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..66.

Eric Weisstein's World of Mathematics, Redheffer Matrix

EXAMPLE

{1},

{1, -1},

{0, -2, 1},

{-1, -1,3, -1},

{-1, 1, 3, -4, 1},

{-2, 5, -1, -6, 5, -1},

{-1, 5, -6, -3, 10, -6, 1},

{-2, 11, -21, 13, 8, -15, 7, -1},

{-2, 13, -33, 38, -11, -19, 21, -8, 1},

{-2, 16, -52, 86, -69,7, 34, -28, 9, -1},

{-1, 12, -54, 124, -155, 90, 13, -56, 36, -10, 1}

MATHEMATICA

Redheffer[d_] := SparseArray[{{i_, 1} -> 1, {i_, j_} /; Mod[j, i] == 0 -> 1}, {d, d}]

a = Join[{{1}}, Table[CoefficientList[CharacteristicPolynomial[Redheffer[d], x], x], {d, 1, 10}]]

Flatten[a]

CROSSREFS

Cf. A140865.

Sequence in context: A115622 A294892 A108886 * A001492 A347049 A054576

Adjacent sequences:  A140883 A140884 A140885 * A140887 A140888 A140889

KEYWORD

tabl,sign

AUTHOR

Roger L. Bagula and Gary W. Adamson, Jul 23 2008

EXTENSIONS

Edited by Joerg Arndt, May 30 2021

STATUS

approved

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Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)